No! Sports drinks and flavored waters are much like soda and juice in that they are all sugar-containing beverages.
Unlike soda, many of these drinks have clever packaging that can lead the buyer to assume they are healthy, such as prominently displaying on a label that it contains vitamin C, antioxidants, or is natural. However, sports drinks, fruit drinks, and the like do not add to a healthy diet. On the contrary, they are one of the most frequent sources of added sugar in the diet of children in the U.S.
The healthiest options for children over the age of one are water and milk. Adding a squeeze of lemon, lime, or orange can make the flavor a bit more interesting without adding sugar. This is true for little athletes, too. There is nothing essential in a sports drink for a toddler athlete. Stick with water.